Bariumbromiddihydrat

Lutz, H. D.; Engelen, B.; Freiburg, C.

doi:10.1107/s0567740880003421

Cited by 7 publications

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“…A numerical absorption correction did not improve the results. The final ratio of maximum least-squares shift to Brought to you by | provisional account Unauthenticated Download Date | 6/22/15 8:05 AM Lutz, Engelen and Freiburg (1980) are given in square brackets for comparison.…”

Section: Methodsmentioning

confidence: 99%

“…'s are given in parentheses. X-ray data (Lutz, Engelen and Freiburg, 1980) during data collection. After data reduction, merging of symmetryequivalent reflections yielded 427 unique reflections, Ä int = 0.0315.…”

Section: Methodsmentioning

confidence: 99%

“…After data reduction, merging of symmetryequivalent reflections yielded 427 unique reflections, Ä int = 0.0315. The starting values for the Ba, Br, and O positions were taken from X-ray data (Lutz, Engelen and Freiburg, 1980), the hydrogen positions were determined from subsequent difference Fourier syntheses. Scattering lengths for all atoms were taken from Sears (1986): b Bi = 5.25(4), ¿> Br = 6.79(2), b 0 = 5.803(4), b H = -3.739(1) fm.…”

Section: Methodsmentioning

confidence: 99%

“…The hydrogen atoms (and OH bonds) are therefore crystallographically not equivalent, their true positions being unknown so far. Two possible orientations for the water molecule have been discussed in the literature: an almost tetrahedral [Br 2 (H 2 0) 2 ] 2 " unit (Bang, 1961;McGrath, 1965) and additionally an approximately square planar [Br 2 (H 2 0) 2 ] 2_ arrangement (Lutz, Engelen and Freiburg, 1980). Detailed infrared and Raman spectroscopic studies (Lutz, Pobitschka, Frischemeier and Becker, 1978) showed that only one OH (OD) stretching frequency is observed for isotopically dilute samples indicating that the two OH bonds are energetically equivalent, although the respective O w -Br distances from X-ray data are significantly different for both possible arrangements.…”

Section: Introductionmentioning

confidence: 99%

“…The structure of BaBr 2 • 2H 2 0, which is the stable hydrate of barium bromide at room temperature, has been determined by Bang (1961) and refined by Lutz, Engelen and Freiburg (1980). There is only one kind of water of crystallization, which occupies an 8/ site, site symmetry 1.…”

Section: Introductionmentioning

confidence: 99%

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Local pseudosymmetry of the water molecule in BaBr₂ · 2H₂O, a neutron diffraction study

Kellersohn¹,

Engelen²,

Lutz³

et al. 1991

Zeitschrift Für Kristallographie - Crystalline Materials

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Barium bromide dihydrate, BaBr 2 · 2H 2 0, M r = 333.188, monoclinic C2/c, a = 1042.9(1), è = 719.5(1), c = 837.5(1) pm, β = 113.60(1)°, V= 0.5759(1) nm 3 , Ζ = 4, D x = 3.843 Mg · m" 3 ,/l(neutron) = 123.75 pm, /i(calc.) = 0.146 mm" 1 , F\000) = 61.746 fm, Γ =297 Κ, R = 0.0494, wR = 0.0469 for 370 observed unique reflections. The present neutron diffraction study confirms the results of X-ray structure determination with respect to the heavy atoms. Additionally, previous spectroscopic findings can now be related to structural features. The energetic equivalence of the two crystallographically independent OH bonds can be explained by (i) the very similar hydrogen bond lengths [Η···ΒΓ: 243.7(6) and 244.3(7) pm] and (ii) the symmetric coordination sphere of the tetrahedrally coordinated water molecules. The occurence of almost tetrahedral * Author to whom correspondence should be addressed. Brought to you by | provisional account Unauthenticated Download Date | 6/22/15 8:05 AM 176 Th. Kellersohn et al.[Br 2 (H 2 0) 2 ] 2 ~ units enables significant intermolecular vibrational interactions of the water molecules, which explains the unusually large Davydov splittings of the water bands.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%